set(a 1)

if(DEFINED a)
	message("DEFINED a为真")
endif()

if(CACHE{b})
else()
	message("CACHE{b}为假")
endif()

if(COMMAND set)
	message("COMMAND set为真")
endif()

if(EXISTS "${CMAKE_CURRENT_LIST_DIR}/logic.cmake")
	message("EXISTS \"${CMAKE_CURRENT_LIST_DIR}/logic.cmake\"为真")
endif()
